1. Field of the Invention
The present invention pertains to patient interface devices structured to deliver a flow of breathing gas to a user, and, in particular, to a cradle style sealing cushion for a patient interface device that has side stabilizers providing an improved fit and seal.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube into the patient's esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver positive airway pressure (PAP) therapy to treat certain medical disorders, the most notable of which is OSA. Known PAP therapies include continuous positive airway pressure (CPAP), wherein a constant positive pressure is provided to the airway of the patient in order to splint open the patient's airway, and variable airway pressure, wherein the pressure provided to the airway of the patient is varied with the patient's respiratory cycle. Such therapies are typically provided to the patient at night while the patient is sleeping.
Non-invasive ventilation and pressure support therapies as just described involve the placement of a patient interface device including a mask component having a soft, flexible sealing cushion on the face of a patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal/oral mask that covers the patient's nose and mouth, or a full face mask that covers the patient's face. Such patient interface devices may also employ other patient contacting components, such as forehead supports, cheek pads and chin pads. The patient interface device is connected to a gas delivery tube or conduit and interfaces the ventilator or pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head.
One type of known sealing cushion is called a cradle style sealing cushion. A cradle style sealing cushion is structured to rest beneath the patient's nose and provides an air-tight seal against the surfaces of the nasal septum and nostrils (and also possibly the upper lip). One major disadvantage of current cradle style sealing cushions is that the seal between the cushion and the nose is very sensitive to the alignment of the cushion to the nose. For this reason, many wearers find it difficult to maintain a reliable seal when using a mask with a cradle style sealing cushion due to misalignment caused by movement of the wearer or external forces acting on the mask (e.g. from a bed pillow). When the seal is broken, the ability of the respiratory therapy device to deliver adequate airflow to the wearer may be compromised. Additionally, air leakage may be directed into the wearer's face, causing discomfort.